Ni-doped versus undoped Mg-MgH2 materials for high temperature heat or hydrogen storage
Ni-doped versus undoped Mg-MgH2 materials for high temperature heat or hydrogen storage
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DOI：
10.1016/s0925-8388(99)00109-7
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发表时间：
1999-11-15
影响因子：
6.2
通讯作者：
Wessel, S
中科院分区：
文献类型：
--
作者：
Bogdanovic, B;Hofmann, H;Wessel, S
第一次在宽范围的氢化/脱氢（循环）条件下对用于可逆（热化学）高温热或氢储存的各种Ni掺杂和未掺杂的Mg-MgH 2材料的行为进行了比较研究（参见图5）。发现在循环测试过程中观察到的存储容量损失敏感地依赖于所施加的循环条件的所有细节，并且可以是暂时的（可逆的）或持久的（不可逆的）性质。基于通过光学显微镜的研究，可逆容量损失似乎与在强化循环条件下在Ni掺杂的Mg颗粒表面上过高的MgH 2成核位点形成速率有关;- 不可逆容量损失，尤其在Ni掺杂材料的情况下显著，是材料颗粒在脱氢反应器中烧结的结果。Ni掺杂的Mg-MgH 2材料即使在非常温和的压力下也具有优异的循环稳定性和高氢化速率。温度循环条件（所谓的标准循环条件或低于标准循环条件[B.波格丹诺维，Th. Hartwig; B. Spliethoff，国际氢能杂志18（1993）575;项目编号0328939 C的最终报告，F.R.G.的联邦研究和技术部，Bonn（1992）]），适用于诸如太阳能产生热和冷、热泵、氢储存等应用。另一方面，基于它们的循环稳定性和在苛刻的反应条件下的足够的反应速率，通过刷涂制备的纯Mg粉末可以用作用于在450-500 ℃的温度范围内可逆热化学高温储热的目的的廉价材料，储热容量达到0.6- 0.7kWh/kg Mg，适用于通过斯特林发动机进行太阳能发电或在上述温度范围内储存工业热量。(C)1999年Elsevier Science S.A. All rights reserved.
A comparative study of the behavior of various Ni-doped and undoped Mg-MgH2 materials to be utilized for reversible (thermochemical) high temperature heat or hydrogen storage has for the first time been conducted over a broad range of hydrogenation/dehydrogenation (cycling) conditions (see Fig. 5). The storage capacity losses observed in the course of cyclic tests are found to be sensitively dependent to all the details of the applied cycling conditions and can be of temporary (reversible) or persistent (irreversible) nature. Based upon investigations via optical microscopy, the reversible capacity losses appear to be associated with an excessively high formation rate of MgH2-nucleation sites on the surface of Ni-doped Mg particles under intensified cycling conditions; irreversible capacity losses, especially pronounced in the case of Ni-doped materials, are the result of sintering of the material particles in the dehydrogenated (metallic) form upon prolonged cycling at higher temperatures.Ni-doped Mg-MgH2 materials have excellent cyclic stability and high hydrogenation rates even under very mild pressure/temperature cycling conditions (so-called standard cycling conditions or below them [B. Bogdanovie, Th. Hartwig; B. Spliethoff, Int. J. Hydrogen Energy 18 (1993) 575; Final Report of Project No. 0328939 C, Federal Ministry for Research and Technology of the F.R.G., Bonn (1992)]) suitable for applications such as solar generation of heat and cold, heat pumps, hydrogen storage, and the Like. On the other hand, based on their cyclic stability and sufficient reaction rates under severe reaction conditions, neat Mg powders produced by brushing can be used as cheap materials for the purpose of reversible thermochemical high temperature heat storage in the temperature range of 450-500 degrees C with heat storage capacities amounting to 0.6-0.7 kWh/kg Mg, applicable for solar power generation via Stirling engines or storage of industrial heat in the above temperature ranges. (C) 1999 Elsevier Science S.A. All rights reserved.